i. Selection of dyeing auxiliaries: In the dyeing process, in order to improve the dyeing performance of dyes, dyeing auxiliaries are usually added. The auxiliary uses anionic and non-anionic leveling agents, and the dosage is 0.5g/l-1.0g /l, if the dosage is too high, the dispersibility at high temperature will decrease.
ii. Selection of dyeing-solvent ratio: In high temperature and high pressure dyeing, the change of the solvent ratio will affect the dyeing rate, especially the coverage. The dyes with good migration, high solubility and high affinity for water have a large dependence on the solubility ratio, and should be strictly controlled to prevent batch difference.
iii. Selection of PH value for dyeing and dissolving: dyeing water, auxiliaries, alkaline agent left in fabric pretreatment and auxiliaries added during dye manufacture all have certain influence on PH value. Excessive PH value will cause some disperse dyes The discoloration is caused by the hydrolysis of the molecular structure, and the general pH is controlled between 4.5-5.5.
iv. Selection of dyeing water:
If hard water is used or metal ions Ca++, Fe+++, Fe++, etc. are mixed into the dyeing liquid, the color of the dyed matter will be dull, so the hardness of the dyeing water should be controlled within 100PPM.